隧道穿越活动断裂带液压破碎锤开挖施工技术

Construction Technology of Using Hydraulic Breaker to Excavate Tunnels in Active Fault Zones

本文对隧道穿越活动断裂带因采用爆破法开挖出现的围岩变形大、超挖严重等问题进行施工技术研究。根据新奥法"保护围岩"施工理念,以削弱对围岩的施工扰动来减小围岩变形作为控制变形和超挖的基础,从机械破碎岩体代替爆破开挖入手,选择铣挖机和破碎锤现场进行开挖试验,最终确定以破碎锤作为隧道开挖碎岩设备;利用微三台阶法,实现快速开挖、支护,工序衔接紧凑,以达到减少对洞周遗留岩体扰动和超挖的目的,并确定合理的预留变形量,减少不必要开挖断面与衬砌混凝土超方,具有良好的经济效益和社会效益。

Tunneling in active fault zones using blasting with explosives has inherent risks of excessive deformation of the surrounding rock and over excavation. In this paper,we studied the advantages of hydraulic breaker excavation technology in tunneling in active fault zones based on the New Austrian Tunneling Method construction concept of utilizing the strength of the surrounding rock mass. Deformation and over excavation were controlled by reducing construction disturbance and surrounding rock deformation,and the rock mass was crushed using mechanical means instead of blasting. After conducting field excavation test using a milling machine and a hydraulic breaker,the hydraulic breaker was selected as the equipment to break rocks in the tunneling excavation. The mini three-bench tunneling method was adopted for quick excavation and to support the tunnel construction,providing a more cohesive excavation approach,which helped reduce disturbance and over excavation of the remaining rock mass around the tunnel. In addition,a reasonable amount of reserved deformation was confirmed to reduce unnecessary cross-section excavation and oversizing of the lining concrete,which made the tunneling more economical and provided social benefits.